1
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Scalia P, Williams SJ, Fujita-Yamaguchi Y, Giordano A. Cell cycle control by the insulin-like growth factor signal: at the crossroad between cell growth and mitotic regulation. Cell Cycle 2023; 22:1-37. [PMID: 36005738 PMCID: PMC9769454 DOI: 10.1080/15384101.2022.2108117] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In proliferating cells and tissues a number of checkpoints (G1/S and G2/M) preceding cell division (M-phase) require the signal provided by growth factors present in serum. IGFs (I and II) have been demonstrated to constitute key intrinsic components of the peptidic active fraction of mammalian serum. In vivo genetic ablation studies have shown that the cellular signal triggered by the IGFs through their cellular receptors represents a non-replaceable requirement for cell growth and cell cycle progression. Retroactive and current evaluation of published literature sheds light on the intracellular circuitry activated by these factors providing us with a better picture of the pleiotropic mechanistic actions by which IGFs regulate both cell size and mitogenesis under developmental growth as well as in malignant proliferation. The present work aims to summarize the cumulative knowledge learned from the IGF ligands/receptors and their intracellular signaling transducers towards control of cell size and cell-cycle with particular focus to their actionable circuits in human cancer. Furthermore, we bring novel perspectives on key functional discriminants of the IGF growth-mitogenic pathway allowing re-evaluation on some of its signal components based upon established evidences.
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Affiliation(s)
- Pierluigi Scalia
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,CST, Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, United states,CONTACT Pierluigi Scalia ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA9102, USA
| | - Stephen J Williams
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,CST, Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, United states
| | - Yoko Fujita-Yamaguchi
- Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Antonio Giordano
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,School of Medical Biotechnology, University of Siena, Italy
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2
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Ahmadifar E, Eslami M, Kalhor N, Zaretabar A, Mohammadzadeh S, Shahriari Moghadam M, Yousefi M, Ahmadifar M, Hoseinifar SH, Pusadee T, van Doan H. Effect of a diet enriched with sodium propionate on growth performance, antioxidant property, innate-adaptive immune response, and growth-related genes expression in critically endangered beluga sturgeon (Huso huso). FISH & SHELLFISH IMMUNOLOGY 2022; 125:101-108. [PMID: 35472403 DOI: 10.1016/j.fsi.2022.04.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/03/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Organic acids are active substances required for improving the productivity and wellbeing of aquatic animals. Herein, the study investigated the effects of sodium propionate on growth performance, antioxidative and immune responses, and growth-related genes expression in beluga sturgeon (Huso huso). For eight weeks, fish fed sodium propionate at 0, 1.2, 2.5, and 5 g kg-1. The final weight, weight gain, and SGR were substantially increased while FCR decreased by dietary sodium propionate at 2.5 and 5 g kg-1 (P < 0.05). The expression of Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) was markedly upregulated (P < 0.05) by dietary sodium propionate in the gills and livers of beluga. The highest mRNA level of GH and IGF-1 has been observed in fish fed a 2.5 g sodium propionate/kg diet. The red blood cells count, and hemoglobin level were meaningfully increased (P < 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg-1 levels. Further, the hematocrit level was increased (P < 0.05) by a dietary 5 g sodium propionate/kg diet. The total protein level and lysozyme activity were meaningfully increased (P < 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg-1 levels. The highest superoxide dismutase was observed in fish fed 2.5 g sodium propionate/kg diet. Catalase activity was significantly higher in fish fed 5 g kg-1 than 1.2 g kg-1. The glutathione peroxidase activity was markedly higher in fish fed 2.5, and 5 g kg-1 than fish fed control diet. The lowest malondialdehyde levels were observed in fish fed 1.2, and 2.5 g sodium propionate/kg diets. Moreover, the highest mucosal total protein, total immunoglobulin and lysozyme were recorded in fish fed 2.5, and 5 g sodium propionate/kg diets. The obtained results indicate that dietary sodium propionate is recommended at 2.5-5 g kg-1 to improve beluga sturgeon's growth performance, feed utilization, and wellbeing.
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Affiliation(s)
- Ehsan Ahmadifar
- Department of Fisheries, Faculty of Natural Resources, University of Zabol, Zabol, Iran.
| | | | - Naser Kalhor
- Department of Mesanchymal Stem Cell, Academic Center for Education, Culture and Research, Qom Branch, Qom, Iran
| | - Amine Zaretabar
- Fisheries Department, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
| | - Sedigheh Mohammadzadeh
- Fisheries Department, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
| | - Mohsen Shahriari Moghadam
- Department of Environmental Sciences, Faculty of Natural Resources, University of Zabol, Zabol, Iran
| | - Morteza Yousefi
- Department of Veterinary Medicine, Peoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya St, Moscow 117198, Russian Federation
| | - Mehdi Ahmadifar
- Department of Stem Cell Biology and Technology of ACECR, Royan Institute, Cell Science Research Center, Collage of Stem Cell and Developmental Biology, Tehran, Iran
| | - Seyed Hossein Hoseinifar
- Department of Fisheries, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
| | - Tonapha Pusadee
- Department of Plant and Soil Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand; Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Hien van Doan
- Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand; Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand.
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3
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Qian Y, Berryman DE, Basu R, List EO, Okada S, Young JA, Jensen EA, Bell SRC, Kulkarni P, Duran-Ortiz S, Mora-Criollo P, Mathes SC, Brittain AL, Buchman M, Davis E, Funk KR, Bogart J, Ibarra D, Mendez-Gibson I, Slyby J, Terry J, Kopchick JJ. Mice with gene alterations in the GH and IGF family. Pituitary 2022; 25:1-51. [PMID: 34797529 PMCID: PMC8603657 DOI: 10.1007/s11102-021-01191-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/21/2021] [Indexed: 01/04/2023]
Abstract
Much of our understanding of GH's action stems from animal models and the generation and characterization of genetically altered or modified mice. Manipulation of genes in the GH/IGF1 family in animals started in 1982 when the first GH transgenic mice were produced. Since then, multiple laboratories have altered mouse DNA to globally disrupt Gh, Ghr, and other genes upstream or downstream of GH or its receptor. The ability to stay current with the various genetically manipulated mouse lines within the realm of GH/IGF1 research has been daunting. As such, this review attempts to consolidate and summarize the literature related to the initial characterization of many of the known gene-manipulated mice relating to the actions of GH, PRL and IGF1. We have organized the mouse lines by modifications made to constituents of the GH/IGF1 family either upstream or downstream of GHR or to the GHR itself. Available data on the effect of altered gene expression on growth, GH/IGF1 levels, body composition, reproduction, diabetes, metabolism, cancer, and aging are summarized. For the ease of finding this information, key words are highlighted in bold throughout the main text for each mouse line and this information is summarized in Tables 1, 2, 3 and 4. Most importantly, the collective data derived from and reported for these mice have enhanced our understanding of GH action.
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Affiliation(s)
- Yanrong Qian
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
| | - Darlene E Berryman
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Reetobrata Basu
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
| | - Edward O List
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
| | - Shigeru Okada
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Pediatrics, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Jonathan A Young
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Elizabeth A Jensen
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
- Translational Biomedical Sciences Doctoral Program, Ohio University, Athens, OH, USA
| | - Stephen R C Bell
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Prateek Kulkarni
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, OH, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, USA
| | | | - Patricia Mora-Criollo
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Translational Biomedical Sciences Doctoral Program, Ohio University, Athens, OH, USA
| | - Samuel C Mathes
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
| | - Alison L Brittain
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, USA
| | - Mat Buchman
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Emily Davis
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, OH, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, USA
| | - Kevin R Funk
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, OH, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, USA
| | - Jolie Bogart
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, OH, USA
| | - Diego Ibarra
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Chemistry and Biochemistry, College of Arts and Sciences, Ohio University, Athens, OH, USA
| | - Isaac Mendez-Gibson
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- College of Health Sciences and Professions, Ohio University, Athens, OH, USA
| | - Julie Slyby
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, OH, USA
| | - Joseph Terry
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, OH, USA
| | - John J Kopchick
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA.
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA.
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4
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Kamei H, Duan C. Alteration of organ size and allometric scaling by organ-specific targeting of IGF signaling. Gen Comp Endocrinol 2021; 314:113922. [PMID: 34606746 DOI: 10.1016/j.ygcen.2021.113922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 08/21/2021] [Accepted: 09/29/2021] [Indexed: 11/16/2022]
Abstract
The size of an organ is proportional to the other body parts or the whole body. This relationship is known as allometry. Understanding how allometry is determined is a fundamental question in biology. Here we tested the hypothesis that local insulin-like growth factor (Igf) signaling is critical in regulating organ size and its allometric scaling by organ-specific expression of Igf binding protein (Igfbp). Overexpression of Igfbp2a or 5b in the developing zebrafish eye, heart, and inner ear resulted in a disproportional reduction in their growth relative to the body. Stable transgenic zebrafish with lens-specific Igfbp5b expression selectively reduced adult eye size. The action is Igf-dependent because an Igf-binding deficient Igfbp5b mutant had no effect. Targeted expression of a dominant-negative Igf1 receptor (dnIgf1r) in the lens caused a similar reduction in relative eye growth. Furthermore, co-expression of IGF-1 with an Igfbp restored the eye size. Finally, co-expression of a constitutively active form of Akt with Igfbp or dnIgf1r restored the relative eye growth. These data suggest that local Igf availability and Igf signaling activity are critical determinants of organ size and allometric scaling in zebrafish.
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Affiliation(s)
- Hiroyasu Kamei
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University 11-4-1, Ossaka, Noto, Ishikawa 927-0552, Japan.
| | - Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, United States
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5
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Gurevich E, Segev Y, Landau D. Growth Hormone and IGF1 Actions in Kidney Development and Function. Cells 2021; 10:cells10123371. [PMID: 34943879 PMCID: PMC8699155 DOI: 10.3390/cells10123371] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/16/2021] [Accepted: 11/24/2021] [Indexed: 01/17/2023] Open
Abstract
Growth hormone (GH) exerts multiple effects on different organs including the kidneys, either directly or via its main mediator, insulin-like-growth factor-1 (IGF-1). The GH/IGF1 system plays a key role in normal kidney development, glomerular hemodynamic regulation, as well as tubular water, sodium, phosphate, and calcium handling. Transgenic animal models demonstrated that GH excess (and not IGF1) may lead to hyperfiltration, albuminuria, and glomerulosclerosis. GH and IGF-1 play a significant role in the early development of diabetic nephropathy, as well as in compensatory kidney hypertrophy after unilateral nephrectomy. Chronic kidney disease (CKD) and its complications in children are associated with alterations in the GH/IGF1 axis, including growth retardation, related to a GH-resistant state, attributed to impaired kidney postreceptor GH-signaling and chronic inflammation. This may explain the safety of prolonged rhGH-treatment of short stature in CKD.
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Affiliation(s)
- Evgenia Gurevich
- Department of Nephrology, Schneider Children’s Medical Center of Israel, 14 Kaplan Street, Petach Tikva 4920235, Israel;
| | - Yael Segev
- Shraga Segal Department of Microbiology and Immunology, Ben Gurion University, Beer Sheva 8410501, Israel;
| | - Daniel Landau
- Department of Nephrology, Schneider Children’s Medical Center of Israel, 14 Kaplan Street, Petach Tikva 4920235, Israel;
- Sackler School of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 6997801, Israel
- Correspondence: ; Tel.: +972-3925-3651
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6
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Differential Expression of IGF1, IGFBP5, MSTN, and MYH1 Across Different Age Classes in American Quarter Horses. J Equine Vet Sci 2020; 94:103226. [PMID: 33077104 DOI: 10.1016/j.jevs.2020.103226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 11/22/2022]
Abstract
The objective of this study was to determine the influence of age on expression of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein (IGFBP5), myostatin (MSTN), and myosin (MYH1) genes which are related to growth and muscle development in the American Quarter Horse. Thus, horses (n = 10) from weanling, yearling, 2-, 3-, and 10-year-old age classes were sampled and gene expression was assessed by RT-qPCR. ΔCT was calculated using the hypoxanthine-guanine phosphoribosyltransferase gene as an internal normalizer. The generalized linear model was used to determine differentially expressed genes, by pairwise comparison between ages. Among technical replicates, the coefficient of variation ranged from 1.0 to 5.2% and was lower than the variation observed between biological replicates (2.1-12.9%). IGF1 demonstrated significantly lower expression in the 3-year-old age class than in weanlings and yearlings, but the 10-year-old age class displayed a significantly higher level than 2- and 3-year-old age classes. Expression of IGFBP5 was highest in weanlings compared with all other age classes. Expression of MSTN was significantly higher in weanlings than in other age classes, whereas 10-year-old horses had an intermediate level of expression, but significantly different from yearlings, 2- and 3-year-old fillies. Finally, expression of MYH1 was lower in 2- and 10-year-old horses than in weanlings and yearlings, whereas 3-year-old fillies demonstrated an intermediate level of expression. Differential expression patterns observed in this preliminary study provide insight into the physiological changes occurring throughout the life span of horses. These patterns could also help explain the variation in performance and endurance between individuals at different developmental stages.
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7
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Xi G, Demambro VE, D’Costa S, Xia SK, Cox ZC, Rosen CJ, Clemmons DR. Estrogen Stimulation of Pleiotrophin Enhances Osteoblast Differentiation and Maintains Bone Mass in IGFBP-2 Null Mice. Endocrinology 2020; 161:5805123. [PMID: 32168373 PMCID: PMC7069688 DOI: 10.1210/endocr/bqz007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 03/12/2020] [Indexed: 12/22/2022]
Abstract
Insulin-like growth factor binding protein-2 (IGFBP-2) stimulates osteoblast differentiation but only male Igfbp2 null mice have a skeletal phenotype. The trophic actions of IGFBP-2 in bone are mediated through its binding to receptor tyrosine phosphatase beta (RPTPβ). Another important ligand for RPTPβ is pleiotrophin (PTN), which also stimulates osteoblast differentiation. We determined the change in PTN and RPTPβ in Igfbp2-/- mice. Analysis of whole bone mRNA in wild-type and knockout mice revealed increased expression of Ptn. Rptpβ increased in gene-deleted animals with females having greater expression than males. Knockdown of PTN expression in osteoblasts in vitro inhibited differentiation, and addition of PTN to the incubation medium rescued the response. Estradiol stimulated PTN secretion and PTN knockdown blocked estradiol-stimulated differentiation. PTN addition to IGFBP-2 silenced osteoblast stimulated differentiation, and an anti-fibronectin-3 antibody, which inhibits PTN binding to RPTPβ, inhibited this response. Estrogen stimulated PTN secretion and downstream signaling in the IGFBP-2 silenced osteoblasts and these effects were inhibited with anti-fibronectin-3. Administration of estrogen to wild-type and Igfbp2-/- male mice stimulated an increase in both areal bone mineral density and trabecular bone volume fraction but the increase was significantly greater in the Igfbp2-/- animals. Estrogen also stimulated RPTPβ expression in the null mice. We conclude that loss of IGFBP-2 expression is accompanied by upregulation of PTN and RPTPβ expression in osteoblasts, that the degree of increase is greater in females due to estrogen secretion, and that this compensatory change may account for some component of the maintenance of normal bone mass in female mice.
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Affiliation(s)
- Gang Xi
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | | | - Susan D’Costa
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | - Shalier K Xia
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | - Zach C Cox
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | | | - David R Clemmons
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
- Correspondence: David R. Clemmons, MD, CB#7170, 8024 Burnett-Womack, Division of Endocrinology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7170. E-mail:
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8
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Khan S. IGFBP-2 Signaling in the Brain: From Brain Development to Higher Order Brain Functions. Front Endocrinol (Lausanne) 2019; 10:822. [PMID: 31824433 PMCID: PMC6883226 DOI: 10.3389/fendo.2019.00822] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
Insulin-like growth factor-binding protein-2 (IGFBP-2) is a pleiotropic polypeptide that functions as autocrine and/or paracrine growth factors. IGFBP-2 is the most abundant of the IGFBPs in the cerebrospinal fluid (CSF), and developing brain showed the highest expression of IGFBP-2. IGFBP-2 expressed in the hippocampus, cortex, olfactory lobes, cerebellum, and amygdala. IGFBP-2 mRNA expression is seen in meninges, blood vessels, and in small cell-body neurons (interneurons) and astrocytes. The expression pattern of IGFBP-2 is often developmentally regulated and cell-specific. Biological activities of IGFBP-2 which are independent of their abilities to bind to insulin-like growth factors (IGFs) are mediated by the heparin binding domain (HBD). To execute IGF-independent functions, some IGFBPs have shown to bind with their putative receptors or to translocate inside the cells. Thus, IGFBP-2 functions can be mediated both via insulin-like growth factor receptor-1 (IGF-IR) and independent of IGF-Rs. In this review, I suggest that IGFBP-2 is not only involved in the growth, development of the brain but also with the regulation of neuronal plasticity to modulate high-level cognitive operations such as spatial learning and memory and information processing. Hence, IGFBP-2 serves as a neurotrophic factor which acts via metaplastic signaling from embryonic to adult stages.
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9
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Vassilakos G, Barton ER. Insulin-Like Growth Factor I Regulation and Its Actions in Skeletal Muscle. Compr Physiol 2018; 9:413-438. [PMID: 30549022 DOI: 10.1002/cphy.c180010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The insulin-like growth factor (IGF) pathway is essential for promoting growth and survival of virtually all tissues. It bears high homology to its related protein insulin, and as such, there is an interplay between these molecules with regard to their anabolic and metabolic functions. Skeletal muscle produces a significant proportion of IGF-1, and is highly responsive to its actions, including increased muscle mass and improved regenerative capacity. In this overview, the regulation of IGF-1 production, stability, and activity in skeletal muscle will be described. Second, the physiological significance of the forms of IGF-1 produced will be discussed. Last, the interaction of IGF-1 with other pathways will be addressed. © 2019 American Physiological Society. Compr Physiol 9:413-438, 2019.
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Affiliation(s)
- Georgios Vassilakos
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, USA
| | - Elisabeth R Barton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, USA
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10
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Cleveland BM, Yamaguchi G, Radler LM, Shimizu M. Editing the duplicated insulin-like growth factor binding protein-2b gene in rainbow trout (Oncorhynchus mykiss). Sci Rep 2018; 8:16054. [PMID: 30375441 PMCID: PMC6207780 DOI: 10.1038/s41598-018-34326-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 10/17/2018] [Indexed: 01/10/2023] Open
Abstract
In salmonids, the majority of circulating insulin-like growth factor-I (IGF-I) is bound to IGF binding proteins (IGFBP), with IGFBP-2b being the most abundant in circulation. We used CRISPR/Cas9 methodology to disrupt expression of a functional IGFBP-2b protein by co-targeting for gene editing IGFBP-2b1 and IGFBP-2b2 subtypes, which represent salmonid-specific gene duplicates. Twenty-four rainbow trout were produced with mutations in the IGFBP-2b1 and IGFBP-2b2 genes. Mutant fish exhibited between 8–100% and 2–83% gene disruption for IGFBP-2b1 and IGFBP-2b2, respectively, with a positive correlation (P < 0.001) in gene mutation rate between individual fish. Analysis of IGFBP-2b protein indicated reductions in plasma IGFBP-2b abundance to between 0.04–0.96-fold of control levels. Plasma IGF-I, body weight, and fork length were reduced in mutants at 8 and 10 months post-hatch, which supports that IGFBP-2b is significant for carrying IGF-I. Despite reduced plasma IGF-I and IGFBP-2b in mutants, growth retardation in mutants was less severe between 10 and 12 months post-hatch (P < 0.05), suggesting a compensatory growth response occurred. These findings indicate that gene editing using CRISPR/Cas9 and ligand blotting is a feasible approach for characterizing protein-level functions of duplicated IGFBP genes in salmonids and is useful to unravel IGF-related endocrine mechanisms.
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Affiliation(s)
- Beth M Cleveland
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America.
| | - Ginnosuke Yamaguchi
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Lisa M Radler
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Munetaka Shimizu
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
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11
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Liu C, Xin Y, Bai Y, Lewin G, He G, Mai K, Duan C. Ca 2+ concentration-dependent premature death of igfbp5a-/- fish reveals a critical role of IGF signaling in adaptive epithelial growth. Sci Signal 2018; 11:11/548/eaat2231. [PMID: 30228225 DOI: 10.1126/scisignal.aat2231] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The phenotype gap is a challenge for genetically dissecting redundant endocrine signaling pathways, such as the six isoforms in the insulin-like growth factor binding protein (IGFBP) family. Although overexpressed IGFBPs can inhibit or potentiate IGF actions or have IGF-independent actions, mutant mice lacking IGFBP-encoding genes do not exhibit major phenotypes. We found that although zebrafish deficient in igfbp5a did not show overt phenotypes when raised in Ca2+-rich solutions, they died prematurely in low Ca2+ conditions. A group of epithelial cells expressing igfbp5a take up Ca2+ and proliferate under low Ca2+ conditions because of activation of IGF signaling. Deletion of igfbp5a blunted low Ca2+ stress-induced IGF signaling and impaired adaptive proliferation. Reintroducing zebrafish Igfbp5a, but not its ligand binding-deficient mutant, restored adaptive proliferation. Similarly, adaptive proliferation was restored in zebrafish lacking igfbp5a by expression of human IGFBP5, but not two cancer-associated IGFBP5 mutants. Knockdown of IGFBP5 in human colon carcinoma cells resulted in reduced IGF-stimulated cell proliferation. These results reveal a conserved mechanism by which a locally expressed Igfbp regulates organismal Ca2+ homeostasis and survival by activating IGF signaling in epithelial cells and promoting their proliferation in Ca2+-deficient states. These findings underscore the importance of physiological context when analyzing loss-of-function phenotypes of endocrine factors.
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Affiliation(s)
- Chengdong Liu
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.,The Key Laboratory of Mariculture, Education Ministry of China and College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Yi Xin
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yan Bai
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Grant Lewin
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gen He
- The Key Laboratory of Mariculture, Education Ministry of China and College of Fisheries, Ocean University of China, Qingdao 266003, China.,Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - Kangsen Mai
- The Key Laboratory of Mariculture, Education Ministry of China and College of Fisheries, Ocean University of China, Qingdao 266003, China.,Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - Cunming Duan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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12
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Ghanipoor-Samami M, Javadmanesh A, Burns BM, Thomsen DA, Nattrass GS, Estrella CAS, Kind KL, Hiendleder S. Atlas of tissue- and developmental stage specific gene expression for the bovine insulin-like growth factor (IGF) system. PLoS One 2018; 13:e0200466. [PMID: 30001361 PMCID: PMC6042742 DOI: 10.1371/journal.pone.0200466] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/27/2018] [Indexed: 01/04/2023] Open
Abstract
The insulin-like growth factor (IGF) axis is fundamental for mammalian growth and development. However, no comprehensive reference data on gene expression across tissues and pre- and postnatal developmental stages are available for any given species. Here we provide systematic promoter- and splice variant specific information on expression of IGF system components in embryonic (Day 48), fetal (Day 153), term (Day 277, placenta) and juvenile (Day 365–396) tissues of domestic cow, a major agricultural species and biomedical model. Analysis of spatiotemporal changes in expression of IGF1, IGF2, IGF1R, IGF2R, IGFBP1-8 and IR genes, as well as lncRNAs H19 and AIRN, by qPCR, indicated an overall increase in expression from embryo to fetal stage, and decrease in expression from fetal to juvenile stage. The stronger decrease in expression of lncRNAs (average ―16-fold) and ligands (average ―12.1-fold) compared to receptors (average ―5.7-fold) and binding proteins (average ―4.3-fold) is consistent with known functions of IGF peptides and supports important roles of lncRNAs in prenatal development. Pronounced overall reduction in postnatal expression of IGF system components in lung (―12.9-fold) and kidney (―13.2-fold) are signatures of major changes in organ function while more similar hepatic expression levels (―2.2-fold) are evidence of the endocrine rather than autocrine/paracrine role of IGFs in postnatal growth regulation. Despite its rapid growth, placenta displayed a more stable expression pattern than other organs during prenatal development. Quantitative analyses of contributions of promoters P0-P4 to global IGF2 transcript in fetal tissues revealed that P4 accounted for the bulk of transcript in all tissues but skeletal muscle. Demonstration of IGF2 expression in fetal muscle and postnatal liver from a promoter orthologous to mouse and human promoter P0 provides further evidence for an evolutionary and developmental shift from placenta-specific P0-expression in rodents and suggests that some aspects of bovine IGF expression may be closer to human than mouse.
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Affiliation(s)
- Mani Ghanipoor-Samami
- Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
- JS Davies Epigenetics and Genetics Group, Davies Research Centre, School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Ali Javadmanesh
- Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
- JS Davies Epigenetics and Genetics Group, Davies Research Centre, School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Brian M. Burns
- Centre for Animal Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Rockhampton, Queensland, Australia
| | - Dana A. Thomsen
- Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
- JS Davies Epigenetics and Genetics Group, Davies Research Centre, School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Greg S. Nattrass
- Livestock Systems, South Australian Research and Development Institute (SARDI), Roseworthy, South Australia, Australia
| | - Consuelo Amor S. Estrella
- Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
- JS Davies Epigenetics and Genetics Group, Davies Research Centre, School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Karen L. Kind
- JS Davies Epigenetics and Genetics Group, Davies Research Centre, School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Stefan Hiendleder
- Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
- JS Davies Epigenetics and Genetics Group, Davies Research Centre, School of Animal and Veterinary Sciences, Roseworthy Campus, The University of Adelaide, Roseworthy, South Australia, Australia
- * E-mail:
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Abstract
Insulin-like growth factor-binding proteins (IGFBPs) 1-6 bind IGFs but not insulin with high affinity. They were initially identified as serum carriers and passive inhibitors of IGF actions. However, subsequent studies showed that, although IGFBPs inhibit IGF actions in many circumstances, they may also potentiate these actions. IGFBPs are widely expressed in most tissues, and they are flexible endocrine and autocrine/paracrine regulators of IGF activity, which is essential for this important physiological system. More recently, individual IGFBPs have been shown to have IGF-independent actions. Mechanisms underlying these actions include (i) interaction with non-IGF proteins in compartments including the extracellular space and matrix, the cell surface and intracellular space, (ii) interaction with and modulation of other growth factor pathways including EGF, TGF-β and VEGF, and (iii) direct or indirect transcriptional effects following nuclear entry of IGFBPs. Through these IGF-dependent and IGF-independent actions, IGFBPs modulate essential cellular processes including proliferation, survival, migration, senescence, autophagy and angiogenesis. They have been implicated in a range of disorders including malignant, metabolic, neurological and immune diseases. A more complete understanding of their cellular roles may lead to the development of novel IGFBP-based therapeutic opportunities.
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Affiliation(s)
- L A Bach
- Department of Medicine (Alfred)Monash University, Melbourne, Australia
- Department of Endocrinology and DiabetesAlfred Hospital, Melbourne, Australia
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14
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Pulmonary alveolar type I cell population consists of two distinct subtypes that differ in cell fate. Proc Natl Acad Sci U S A 2018; 115:2407-2412. [PMID: 29463737 PMCID: PMC5877944 DOI: 10.1073/pnas.1719474115] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pulmonary alveolar type I (AT1) cells are essential for the gas-exchange function of lungs. AT1 cells retain their cellular plasticity during injury-induced alveolar regeneration. However, we know very little about the developmental heterogeneity of the AT1 cell population. Our study identified a robust genetic marker of postnatal AT1 cells, insulin-like growth factor-binding protein 2 (Igfbp2). We use this marker to demonstrate that the postnatal AT1 cell population actually consists of two AT1 cell subtypes (Hopx+Igfbp2+ and Hopx+Igfbp2− AT1 cells) with distinct cell fates during alveolar regeneration. The large majority of adult AT1 cells expresses Igfbp2 and cannot transdifferentiate into AT2 cells during post pneumonectomy formation of new alveoli. Therefore, Hopx+Igfbp2+ AT1 cells represent the terminally differentiated population of AT1 cells. Pulmonary alveolar type I (AT1) cells cover more than 95% of alveolar surface and are essential for the air–blood barrier function of lungs. AT1 cells have been shown to retain developmental plasticity during alveolar regeneration. However, the development and heterogeneity of AT1 cells remain largely unknown. Here, we conducted a single-cell RNA-seq analysis to characterize postnatal AT1 cell development and identified insulin-like growth factor-binding protein 2 (Igfbp2) as a genetic marker specifically expressed in postnatal AT1 cells. The portion of AT1 cells expressing Igfbp2 increases during alveologenesis and in post pneumonectomy (PNX) newly formed alveoli. We found that the adult AT1 cell population contains both Hopx+Igfbp2+ and Hopx+Igfbp2− AT1 cells, which have distinct cell fates during alveolar regeneration. Using an Igfbp2-CreER mouse model, we demonstrate that Hopx+Igfbp2+ AT1 cells represent terminally differentiated AT1 cells that are not able to transdifferentiate into AT2 cells during post-PNX alveolar regeneration. Our study provides tools and insights that will guide future investigations into the molecular and cellular mechanism or mechanisms underlying AT1 cell fate during lung development and regeneration.
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15
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Garcia de la Serrana D, Macqueen DJ. Insulin-Like Growth Factor-Binding Proteins of Teleost Fishes. Front Endocrinol (Lausanne) 2018; 9:80. [PMID: 29593649 PMCID: PMC5857546 DOI: 10.3389/fendo.2018.00080] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/22/2018] [Indexed: 11/21/2022] Open
Abstract
The insulin-like growth factor (Igf) binding protein (Igfbp) family has a broad range of physiological functions and a fascinating evolutionary history. This review focuses on the Igfbps of teleost fishes, where genome duplication events have diversified gene repertoire, function, and physiological regulation-with six core Igfbps expanded into a family of over twenty genes in some lineages. In addition to briefly summarizing the current state of knowledge on teleost Igfbp evolution, function, and expression-level regulation, we highlight gaps in our understanding and promising areas for future work.
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Affiliation(s)
- Daniel Garcia de la Serrana
- School of Biology, Scottish Oceans Institute, University of St Andrews, St Andrews, United Kingdom
- *Correspondence: Daniel Garcia de la Serrana,
| | - Daniel J. Macqueen
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
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16
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Allard JB, Duan C. IGF-Binding Proteins: Why Do They Exist and Why Are There So Many? Front Endocrinol (Lausanne) 2018; 9:117. [PMID: 29686648 PMCID: PMC5900387 DOI: 10.3389/fendo.2018.00117] [Citation(s) in RCA: 301] [Impact Index Per Article: 50.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/08/2018] [Indexed: 12/11/2022] Open
Abstract
Insulin-like growth factors (IGFs) are key growth-promoting peptides that act as both endocrine hormones and autocrine/paracrine growth factors. In the bloodstream and in local tissues, most IGF molecules are bound by one of the members of the IGF-binding protein (IGFBP) family, of which six distinct types exist. These proteins bind to IGF with an equal or greater affinity than the IGF1 receptor and are thus in a key position to regulate IGF signaling globally and locally. Binding to an IGFBP increases the half-life of IGF in the circulation and blocks its potential binding to the insulin receptor. In addition to these classical roles, IGFBPs have been shown to modulate IGF signaling locally under various conditions. Although members of the IGFBP family share significant sequence homology, they each have unique structural features and play distinct roles. These IGFBP genes also have different modes of regulation and distinct expression patterns. Some IGFBPs have been found to bind to their own receptors or to translocate into the interior compartments of cells where they may execute IGF-independent actions. In spite of this functional and regulatory diversity, it has been puzzling that loss-of-function studies have yielded relatively little information about the physiological functions of IGFBPs. In this review, we suggest that evolution has tended to retain an array of IGFBPs in order to facilitate fine-tuning of IGF signaling. We explore the emerging explanation that many IGFBP functions have evolved to allow the targeted adjustment of IGF signaling under stressful or irregular conditions, which would likely not be revealed in a standard laboratory setting.
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17
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Mazerbourg S, Monget P. Insulin-Like Growth Factor Binding Proteins and IGFBP Proteases: A Dynamic System Regulating the Ovarian Folliculogenesis. Front Endocrinol (Lausanne) 2018; 9:134. [PMID: 29643837 PMCID: PMC5890141 DOI: 10.3389/fendo.2018.00134] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/14/2018] [Indexed: 12/22/2022] Open
Abstract
The aim of the present article is to update our understanding of the expression of the insulin-like growth factor binding proteins (IGFBPs), IGFBP proteases and their implication in the different processes of ovarian folliculogenesis in mammals. In the studied species, IGFs and several small-molecular weight IGFBPs (in particular IGFBP-2 and IGFBP-4) are considered, respectively, as stimulators and inhibitors of follicular growth and maturation. IGFs play a key role in sensitizing ovarian granulosa cells to FSH action during terminal follicular growth. Concentrations of IGFBP-2 and IGFBP-4 in follicular fluid strongly decrease during follicular growth, leading to an increase in IGF bioavailability. Inversely, atresia is characterized by an increase of IGFBP-2 and IGFBP-4 levels, leading to a decrease in IGF bioavailability. Changes in intrafollicular IGFBPs content are due to variations in mRNA expression and/or proteolytic degradation by the pregnancy-associated plasma protein-A (PAPP-A), and likely participates in the selection of dominant follicles. The identification of PAPP-A2, as an IGFBP-3 and -5 protease, and stanniocalcins (STCs) as inhibitors of PAPP-A activity extends the IGF system. Studies on their implication in folliculogenesis in mammals are still in the early stages.
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Affiliation(s)
- Sabine Mazerbourg
- Université de Lorraine, CNRS, CRAN, Nancy, France
- *Correspondence: Sabine Mazerbourg, ; Philippe Monget,
| | - Philippe Monget
- INRA, Physiologie de la Reproduction et des Comportements, UMR 6078 INRA-CNRS-Université de Tours, Nouzilly, France
- *Correspondence: Sabine Mazerbourg, ; Philippe Monget,
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18
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Hoseinifar SH, Safari R, Dadar M. Dietary sodium propionate affects mucosal immune parameters, growth and appetite related genes expression: Insights from zebrafish model. Gen Comp Endocrinol 2017; 243:78-83. [PMID: 27838381 DOI: 10.1016/j.ygcen.2016.11.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/24/2016] [Accepted: 11/08/2016] [Indexed: 12/29/2022]
Abstract
Propionate is a short-chain fatty acid (SCFA) that improves physiological and pathophysiological properties. However, there is limited information available about the effects of SCFAs on mucosal immune parameters as well as growth and appetite related genes expression. The aim of the present study was to evaluate the effect of sodium propionate (SP) intake on the mucosal immune parameters, growth and appetite related genes expression using zebrafish (Danio rerio) as model organism. Zebrafish fed control or diet supplemented with different levels (0.5, 1 and 2%) of SP for 8weeks. At the end of feeding trial, the expression of the key genes related to growth and appetite (GH, IGF1, MYSTN and Ghrl) was evaluated. Also, mucosal immune parameters (Total Ig, lysozyme and protease activity) were studied in skin mucus of zebrafish. The results showed that dietary administration of SP significantly (P<0.05) up-regulated the expression of GH, IGF1 and down-regulated MYSTN gene. Also, feeding zebrafish with SP supplemented diet significantly increased appetite related gene expression (P<0.05) with a more pronounced effect in higher inclusion levels. Compared with control group, the expression of appetite related gene (Ghrl) was remarkably (P<0.05) higher in SP fed zebrafish. Also, elevated mucosal immune parameters was observed in zebrafish fed SP supplemented diet. The present results revealed beneficial effects of dietary SP on mucosal immune response and growth and appetite related genes expression. These results also highlighted the potential use of SP as additive in human diets.
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Affiliation(s)
- Seyed Hossein Hoseinifar
- Department of Fisheries, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
| | - Roghieh Safari
- Department of Fisheries, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
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19
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Swiderski K, Martins KJB, Chee A, Trieu J, Naim T, Gehrig SM, Baum DM, Brenmoehl J, Chau L, Koopman R, Gregorevic P, Metzger F, Hoeflich A, Lynch GS. Skeletal muscle-specific overexpression of IGFBP-2 promotes a slower muscle phenotype in healthy but not dystrophic mdx mice and does not affect the dystrophic pathology. Growth Horm IGF Res 2016; 30-31:1-10. [PMID: 27544574 DOI: 10.1016/j.ghir.2016.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/25/2016] [Accepted: 07/27/2016] [Indexed: 01/14/2023]
Abstract
OBJECTIVE The insulin-like growth factor binding proteins (IGFBPs) are thought to modulate cell size and homeostasis via IGF-I-dependent and -independent pathways. There is a considerable dearth of information regarding the function of IGFBPs in skeletal muscle, particularly their role in the pathophysiology of Duchenne muscular dystrophy (DMD). In this study we tested the hypothesis that intramuscular IGFBP-2 overexpression would ameliorate the pathology in mdx dystrophic mice. DESIGN 4week old male C57Bl/10 and mdx mice received a single intramuscular injection of AAV6-empty or AAV6-IGFBP-2 vector into the tibialis anterior muscle. At 8weeks post-injection the effect of IGFBP-2 overexpression on the structure and function of the injected muscle was assessed. RESULTS AAV6-mediated IGFBP-2 overexpression in the tibialis anterior (TA) muscles of 4-week-old C57BL/10 and mdx mice reduced the mass of injected muscle after 8weeks, inducing a slower muscle phenotype in C57BL/10 but not mdx mice. Analysis of inflammatory and fibrotic gene expression revealed no changes between control and IGFBP-2 injected muscles in dystrophic (mdx) mice. CONCLUSIONS Together these results indicate that the IGFBP-2-induced promotion of a slower muscle phenotype is impaired in muscles of dystrophin-deficient mdx mice, which contributes to the inability of IGFBP-2 to ameliorate the dystrophic pathology. The findings implicate the dystrophin-glycoprotein complex (DGC) in the signaling required for this adaptation.
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Affiliation(s)
- Kristy Swiderski
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Karen Janet Bernice Martins
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Annabel Chee
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Jennifer Trieu
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Timur Naim
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Stefan Martin Gehrig
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Dale Michael Baum
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Julia Brenmoehl
- Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196, Dummerstorf, Germany
| | - Luong Chau
- Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196, Dummerstorf, Germany
| | - René Koopman
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia
| | - Paul Gregorevic
- Muscle Biology and Therapeutics Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Friedrich Metzger
- F. Hoffmann-La Roche Ltd., pRED, Pharma Research & Early Development, DTA Neuroscience, 4070, Basel, Switzerland
| | - Andreas Hoeflich
- Institute for Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196, Dummerstorf, Germany
| | - Gordon Stuart Lynch
- Basic and Clinical Myology Laboratory, Department of Physiology, University of Melbourne, VIC 3010, Australia.
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20
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Phillips LM, Zhou X, Cogdell DE, Chua CY, Huisinga A, R Hess K, Fuller GN, Zhang W. Glioma progression is mediated by an addiction to aberrant IGFBP2 expression and can be blocked using anti-IGFBP2 strategies. J Pathol 2016; 239:355-64. [PMID: 27125842 DOI: 10.1002/path.4734] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/15/2016] [Accepted: 04/09/2016] [Indexed: 12/24/2022]
Abstract
Insulin-like growth factor binding protein 2 (IGFBP2) overexpression is common in high-grade glioma and is both a strong biomarker of aggressive behaviour and a well-documented prognostic factor. IGFBP2 is a member of the secreted IGFBP family that functions by interacting with circulating IGFs to modulate IGF-mediated signalling. This traditional view of IGFBP2 activities has been challenged by the recognition of the diverse functions and cellular locations of members of the IGFBP family. IGFBP2 has been previously established as a driver of glioma progression to a higher grade. In this study, we sought to determine whether IGFBP2-overexpressing tumours are dependent on continued oncogene expression and whether IGFBP2 is a viable therapeutic target in glioma. We took advantage of the well-characterized RCAS/Ntv-a mouse model to create a doxycycline-inducible IGFBP2 model of glioma and demonstrated that the temporal expression of IGFBP2 has dramatic impacts on tumour progression and survival. Further, we demonstrated that IGFBP2-driven tumours are dependent on the continued expression of IGFBP2, as withdrawal of this oncogenic signal led to a significant decrease in tumour progression and prolonged survival. Inhibition of IGFBP2 also impaired tumour cell spread. To assess a therapeutically relevant inhibition strategy, we evaluated a neutralizing antibody against IGFBP2 and demonstrated that it impaired downstream IGFBP2-mediated oncogenic signalling pathways. The studies presented here indicate that IGFBP2 not only is a driver of glioma progression and a prognostic factor but is also required for tumour maintenance and thus represents a viable therapeutic target in the treatment of glioma. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Lynette M Phillips
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xinhui Zhou
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - David E Cogdell
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Corrine Yingxuan Chua
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Anouk Huisinga
- Department of Pathology, Radboud University Nijmegen Medical Centre, 6500, Nijmegen, The Netherlands
| | - Kenneth R Hess
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Gregory N Fuller
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, Texas, USA.,ISB-MDA Genome Data Analysis Center, The Cancer Genome Atlas, Houston, Texas, USA
| | - Wei Zhang
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, Texas, USA.,ISB-MDA Genome Data Analysis Center, The Cancer Genome Atlas, Houston, Texas, USA.,Department of Cancer Biology, Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
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21
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PAPP-A and the IGF system. ANNALES D'ENDOCRINOLOGIE 2016; 77:90-6. [DOI: 10.1016/j.ando.2016.04.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 04/11/2016] [Indexed: 01/25/2023]
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22
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Garfinkel BP, Arad S, Le PT, Bustin M, Rosen CJ, Gabet Y, Orly J. Proportionate Dwarfism in Mice Lacking Heterochromatin Protein 1 Binding Protein 3 (HP1BP3) Is Associated With Alterations in the Endocrine IGF-1 Pathway. Endocrinology 2015; 156:4558-70. [PMID: 26402843 PMCID: PMC5393342 DOI: 10.1210/en.2015-1668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/18/2015] [Indexed: 01/08/2023]
Abstract
Heterochromatin protein 1 binding protein 3 (HP1BP3) is a recently described histone H1-related protein with roles in chromatin structure and transcriptional regulation. To explore the potential physiological role of HP1BP3, we have previously described an Hp1bp3(-/-) mouse model with reduced postnatal viability and growth. We now find that these mice are proportionate dwarfs, with reduction in body weight, body length, and organ weight. In addition to their small size, microcomputed tomography analysis showed that Hp1bp3(-/-) mice present a dramatic impairment of their bone development and structure. By 3 weeks of age, mice of both sexes have severely impaired cortical and trabecular bone, and these defects persist into adulthood and beyond. Primary cultures of both osteoblasts and osteoclasts from Hp1bp3(-/-) bone marrow and splenocytes, respectively, showed normal differentiation and function, strongly suggesting that the impaired bone accrual is due to noncell autonomous systemic cues in vivo. One major endocrine pathway regulating both body growth and bone acquisition is the IGF regulatory system, composed of IGF-1, the IGF receptors, and the IGF-binding proteins (IGFBPs). At 3 weeks of age, Hp1bp3(-/-) mice exhibited a 60% reduction in circulating IGF-1 and a 4-fold increase in the levels of IGFBP-1 and IGFBP-2. These alterations were reflected in similar changes in the hepatic transcripts of the Igf1, Igfbp1, and Igfbp2 genes. Collectively, these results suggest that HP1BP3 plays a key role in normal growth and bone development by regulating transcription of endocrine IGF-1 components.
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Affiliation(s)
- Benjamin P. Garfinkel
- Department of Biological Chemistry (B.P.G., S.A., J.O.), The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Center for Clinical and Translational Research (P.T.L., C.J.R.), Maine Medical Center Research Institute, Scarborough, Maine 04074; Protein Section (M.B.), Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892; and Department of Anatomy and Anthropology (Y.G.), Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 64239, Israel
| | - Shiri Arad
- Department of Biological Chemistry (B.P.G., S.A., J.O.), The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Center for Clinical and Translational Research (P.T.L., C.J.R.), Maine Medical Center Research Institute, Scarborough, Maine 04074; Protein Section (M.B.), Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892; and Department of Anatomy and Anthropology (Y.G.), Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 64239, Israel
| | - Phuong T. Le
- Department of Biological Chemistry (B.P.G., S.A., J.O.), The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Center for Clinical and Translational Research (P.T.L., C.J.R.), Maine Medical Center Research Institute, Scarborough, Maine 04074; Protein Section (M.B.), Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892; and Department of Anatomy and Anthropology (Y.G.), Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 64239, Israel
| | - Michael Bustin
- Department of Biological Chemistry (B.P.G., S.A., J.O.), The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Center for Clinical and Translational Research (P.T.L., C.J.R.), Maine Medical Center Research Institute, Scarborough, Maine 04074; Protein Section (M.B.), Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892; and Department of Anatomy and Anthropology (Y.G.), Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 64239, Israel
| | - Clifford J. Rosen
- Department of Biological Chemistry (B.P.G., S.A., J.O.), The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Center for Clinical and Translational Research (P.T.L., C.J.R.), Maine Medical Center Research Institute, Scarborough, Maine 04074; Protein Section (M.B.), Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892; and Department of Anatomy and Anthropology (Y.G.), Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 64239, Israel
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DeMambro VE, Le PT, Guntur AR, Maridas DE, Canalis E, Nagano K, Baron R, Clemmons DR, Rosen CJ. Igfbp2 Deletion in Ovariectomized Mice Enhances Energy Expenditure but Accelerates Bone Loss. Endocrinology 2015; 156:4129-40. [PMID: 26230658 PMCID: PMC4606757 DOI: 10.1210/en.2014-1452] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previously, we reported sexually dimorphic bone mass and body composition phenotypes in Igfbp2(-/-) mice (-/-), where male mice exhibited decreased bone and increased fat mass, whereas female mice displayed increased bone but no changes in fat mass. To investigate the interaction between IGF-binding protein (IGFBP)-2 and estrogen, we subjected Igfbp2 -/- and +/+ female mice to ovariectomy (OVX) or sham surgery at 8 weeks of age. At 20 weeks of age, mice underwent metabolic cage analysis and insulin tolerance tests before killing. At harvest, femurs were collected for microcomputed tomography, serum for protein levels, brown adipose tissue (BAT) and inguinal white adipose tissue (IWAT) adipose depots for histology, gene expression, and mitochondrial respiration analysis of whole tissue. In +/+ mice, serum IGFBP-2 dropped 30% with OVX. In the absence of IGFBP-2, OVX had no effect on preformed BAT; however, there was significant "browning" of the IWAT depot coinciding with less weight gain, increased insulin sensitivity, lower intraabdominal fat, and increased bone loss due to higher resorption and lower formation. Likewise, after OVX, energy expenditure, physical activity and BAT mitochondrial respiration were decreased less in the OVX-/- compared with OVX+/+. Mitochondrial respiration of IWAT was reduced in OVX+/+ yet remained unchanged in OVX-/- mice. These changes were associated with significant increases in Fgf21 and Foxc2 expression, 2 proteins known for their insulin sensitizing and browning of WAT effects. We conclude that estrogen deficiency has a profound effect on body and bone composition in the absence of IGFBP-2 and may be related to changes in fibroblast growth factor 21.
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Affiliation(s)
- Victoria E DeMambro
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Phuong T Le
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Anyonya R Guntur
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - David E Maridas
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Ernesto Canalis
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Kenichi Nagano
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Roland Baron
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - David R Clemmons
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Clifford J Rosen
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
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Royall DR, Bishnoi RJ, Palmer RF. Serum IGF-BP2 strongly moderates age's effect on cognition: a MIMIC analysis. Neurobiol Aging 2015; 36:2232-2240. [PMID: 26043140 DOI: 10.1016/j.neurobiolaging.2015.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 03/30/2015] [Accepted: 04/04/2015] [Indexed: 01/13/2023]
Abstract
We have used structural equation models to explicitly distinguish functional status and therefore "dementia-relevant" variance in cognitive task performance (i.e., "δ" for dementia). Our approach is modular and can be directed to other targets. In this analysis, we construct a δ ortholog representing the "cognitive correlates of age" (cAGE). cAGE largely mediates age's effects on dementia severity, as rated by the Clinical Dementia Rating Scale Sum of boxes and has an area under the receiver operating curve = 0.96 for the diagnosis of Alzheimer's Disease versus controls. We then test cAGE's association with serum insulin-like growth factor binding protein 2 (IGF-BP2), which has previously been associated with age-related cognitive changes in animals, and with cortical atrophy in older humans. IGF-BP2's adverse effects on cognition are largely mediated through cAGE, independent of education, ethnicity, gender, depression ratings, serum homocysteine levels, hemoglobin A1c, and apolipoprotein e4 status. This suggests that age-specific cognitive decline may be moderated by IGF-BP2 and that modulation of that protein's function(s) might ameliorate age-specific cognitive impairments.
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Affiliation(s)
- Donald R Royall
- Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX, USA; Department of Medicine, University of Texas Health Science Center, San Antonio, TX, USA; Department of Family and Community Medicine, University of Texas Health Science Center, San Antonio, TX, USA; South Texas Veterans' Health System Audie L. Murphy Division GRECC, San Antonio, TX, USA.
| | - Ram J Bishnoi
- Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX, USA
| | - Raymond F Palmer
- Department of Family and Community Medicine, University of Texas Health Science Center, San Antonio, TX, USA
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25
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IGFBP-2: The dark horse in metabolism and cancer. Cytokine Growth Factor Rev 2015; 26:329-46. [DOI: 10.1016/j.cytogfr.2014.12.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/09/2014] [Indexed: 12/29/2022]
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Yau SW, Azar WJ, Sabin MA, Werther GA, Russo VC. IGFBP-2 - taking the lead in growth, metabolism and cancer. J Cell Commun Signal 2015; 9:125-42. [PMID: 25617050 DOI: 10.1007/s12079-015-0261-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/12/2015] [Indexed: 10/24/2022] Open
Abstract
The activity of the Insulin-like Growth Factors (IGFs) ligands elicited via their receptors and transduced by various intracellular signal pathways is modulated by the IGF Binding Proteins (IGFBPs). Among all the IGFBPs, IGFBP-2 has been implicated in the regulation of IGF activity in most tissue and organs. Besides binding to IGFs in the circulation these IGF-regulatory activities of IGFBP-2 involve interactions with components of the extracellular matrix, cell surface proteoglycans and integrin receptors. In addition to these local peri-cellular activities, IGFBP-2 exerts other key functions within the nucleus, where IGFBP-2 directly or indirectly promotes transcriptional activation of specific genes. All of these IGFBP-2 activities, intrinsic or dependent on IGFs, contribute to its functional roles in growth/development, metabolism and malignancy as evidenced by studies in IGFBP-2 animal models and also by many in vitro studies. Finally, preclinical studies have demonstrated that IGFBP-2 administration can be beneficial in improving metabolic responses (inhibition of adipogenesis and enhanced insulin sensitivity), while blockade of IGFBP-2 appears to be an effective approach to inhibiting tumour growth and metastasis.
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Affiliation(s)
- Steven W Yau
- Deparment of Cell Biology, Hormone Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
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Neumann UH, Chen S, Tam YYC, Baker RK, Covey SD, Cullis PR, Kieffer TJ. IGFBP2 is neither sufficient nor necessary for the physiological actions of leptin on glucose homeostasis in male ob/ob mice. Endocrinology 2014; 155:716-25. [PMID: 24424049 DOI: 10.1210/en.2013-1622] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ability of leptin to improve metabolic abnormalities in models of leptin deficiency, lipodystrophy, and even type 1 diabetes is of significant interest. However, the mechanism by which leptin mediates these effects remains ill-defined. Leptin was recently reported to regulate insulin-like growth factor-binding protein-2 (IGFBP2), and adenoviral overexpression of pharmacological levels of IGFBP2 ameliorates diabetic symptoms in many models of diabetes. We sought to determine the role of physiological levels of IGFBP2 in the glucoregulatory action of leptin. To investigate whether physiological levels of IGFBP2 are sufficient to mimic the action of leptin, we treated male ob/ob mice with low-dose IGFBP2 adenovirus (Ad-IGFBP2) or low-dose leptin. Despite similar levels of circulating IGFBP2, leptin but not Ad-IGFBP2 lowered body weight and plasma insulin and improved glucose and insulin tolerance. To elucidate the role of IGFBP2 in normal glucose homeostasis, we knocked down IGFBP2 in male C57BL/6 mice using small interfering RNA to determine whether this would recapitulate any aspect of the ob/ob phenotype. Despite successful IGFBP2 knockdown, body weight, blood glucose, and plasma insulin were unchanged. Finally, to determine whether IGFBP2 is required for the glucoregulatory actions of leptin, we prevented leptin-mediated increases in IGFBP2 in male ob/ob mice using RNA interference. Even though increases in IGFBP2 were blocked, the ability of leptin to decrease body weight, blood glucose, and plasma insulin levels were unaltered. In conclusion, physiological levels of IGFBP2 are neither sufficient to mimic nor required for the physiological action of leptin.
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Affiliation(s)
- Ursula H Neumann
- Departments of Cellular and Physiological Sciences (U.H.N., R.K.B., T.J.K.), Biochemistry and Molecular Biology (S.C., Y.Y.C.T., S.D.C., P.R.C.), and Surgery (T.J.K.), Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Hjortebjerg R, Flyvbjerg A, Frystyk J. Insulin growth factor binding proteins as therapeutic targets in type 2 diabetes. Expert Opin Ther Targets 2013; 18:209-24. [PMID: 24261835 DOI: 10.1517/14728222.2014.858698] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION The signaling pathways of the insulin-like growth factors (IGFs) have been implicated in the aetiology of type 2 diabetes (T2D) and a number of therapeutic modalities aiming at the IGF-axis have been considered. Administration of IGF-I has been reported to improve insulin sensitivity in healthy subjects and patients with T2D. In recent years, the IGF binding proteins (IGFBPs) have also been associated with metabolic disorders, prompting the idea that IGFBPs play important roles in the pathogenesis of T2D. Thus, by virtue of their role in the regulation of IGF effects, the IGFBPs have emerged as potential biomarkers and therapeutic targets in metabolic syndromes and T2D. AREAS COVERED The article provides an overview on recent findings in clinical and experimental IGFBP-research and addresses the studies that have investigated the potentials of the IGFBPs as therapeutic targets in T2D. EXPERT OPINION There is plenty of therapeutic promise within the IGF system, but further understanding of the IGFs in T2D is necessary to avoid off-target effects. Strong evidence supports the use of IGFBPs as therapeutic targets in the treatment of T2D, and it is not difficult to foresee the use of IGFBPs as part of a combination therapy alongside other anti-diabetic drugs.
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Affiliation(s)
- Rikke Hjortebjerg
- Aarhus University, Department of Clinical Medicine, Medical Research Laboratory, Faculty of Health , DK-8000 Aarhus C , Denmark
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Li Z, Wu Z, Ren G, Zhao Y, Liu D. Expression patterns of insulin-like growth factor system members and their correlations with growth and carcass traits in Landrace and Lantang pigs during postnatal development. Mol Biol Rep 2012; 40:3569-76. [PMID: 23269622 DOI: 10.1007/s11033-012-2430-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/18/2012] [Indexed: 01/24/2023]
Abstract
The IGF system plays important roles in growth. Nevertheless, few data have been reported so far on the expression of IGF system members and their relationship with growth in domestic animals, especially pigs. In this study, hepatic transcript level of IGF1, IGF2, IGF binding protein 2 (IGFBP2), IGFBP3 and IGF 1 receptor (IGF1R), plasma protein level of IGF1 and IGFBP3, and eight growth or carcass traits, including chest circumference, body length, body height (BH), body weight, carcass weight, loin muscle area (LMA), back fat thickness and average daily gain, were measured in fast-growing Landrace and slow-growing Lantang pigs at the age of 1, 27, 90, 150 and 180 days. The results showed that liver mRNA level of IGF1, IGF2 and IGF1R, and blood protein level of IGF1 have a similar developmental profile in both Landrace and Lantang pigs. Their levels were higher at the early age than that at other older ages. Hepatic transcript abundances of the two growth inhibitors, IGFBP2 and IGFBP3, were mostly higher in Lantang pigs than that in Landrace pigs, at 5 examined postnatal stages. The IGF system members' liver mRNA level and/or serum protein level have significant correlation with each other in different age of Landrace or Lantang pigs. Hepatic mRNA level or serum protein level of IGF system members also has significant correlation with investigated traits, especially with BH and LMA, in different age of Lantang or Landrace pigs. Our results revealed the change profiles of porcine IGF system members' liver transcript level and plasma protein level between different pig breeds and different postnatal developmental ages. Moreover, the correlation analysis results suggest that the IGF system members act coordinately to regulate the growth performance and carcass composition in pigs. The information obtained from the present study is important for elucidation of the regulatory mechanism of IGF system underlying growth, and for genetic improvement in pigs.
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Affiliation(s)
- Zicong Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, People's Republic of China
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Abstract
The role of IGF binding protein 2 (IGFBP2) in cell growth is intriguing and largely undefined. Previously we identified IGFBP2 as an extrinsic factor that supports ex vivo expansion of hematopoietic stem cells (HSCs). Here we showed that IGFBP2-null mice have fewer HSCs than wild-type mice. While IGFBP2 has little cell-autonomous effect on HSC function, we found decreased in vivo repopulation of HSCs in primary and secondary transplanted IGFBP2-null recipients. Importantly, bone marrow stromal cells that are deficient for IGFBP2 have significantly decreased ability to support the expansion of repopulating HSCs. To investigate the mechanism by which IGFBP2 supports HSC activity, we demonstrated that HSCs in IGFBP2-null mice had decreased survival and cycling, down-regulated expression of antiapoptotic factor Bcl-2, and up-regulated expression of cell cycle inhibitors p21, p16, p19, p57, and PTEN. Moreover, we found that the C-terminus, but not the RGD domain, of extrinsic IGFBP2 was essential for support of HSC activity. Defective signaling of the IGF type I receptor did not rescue the decreased repopulation of HSCs in IGFBP2-null recipients, suggesting that the environmental effect of IGFBP2 on HSCs is independent of IGF-IR mediated signaling. Therefore, as an environmental factor, IGFBP2 supports the survival and cycling of HSCs.
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Kawai M, Breggia AC, DeMambro VE, Shen X, Canalis E, Bouxsein ML, Beamer WG, Clemmons DR, Rosen CJ. The heparin-binding domain of IGFBP-2 has insulin-like growth factor binding-independent biologic activity in the growing skeleton. J Biol Chem 2011; 286:14670-80. [PMID: 21372140 DOI: 10.1074/jbc.m110.193334] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin-like growth factor-binding protein 2 (IGFBP-2) is a member of a family of six highly conserved IGFBPs that are carriers for the insulin-like growth factors (IGFs). IGFBP-2 levels rise during rapid neonatal growth and at the time of peak bone acquisition. In contrast, Igfbp2(-/-) mice have low bone mass accompanied by reduced osteoblast numbers, low bone formation rates, and increased PTEN expression. In the current study, we postulated that IGFBP-2 increased bone mass partly through the activity of its heparin-binding domain (HBD). We synthesized a HBD peptide specific for IGFBP-2 and demonstrated in vitro that it rescued the mineralization phenotype of Igfbp2(-/-) bone marrow stromal cells and calvarial osteoblasts. Consistent with its cellular actions, the HBD peptide ex vivo stimulated metacarpal periosteal expansion. Furthermore, administration of HBD peptide to Igfbp2(-/-) mice increased osteoblast number, suppressed marrow adipogenesis, restored trabecular bone mass, and reduced bone resorption. Skeletal rescue in the Igfbp2(-/-) mice was characterized by reduced PTEN expression followed by enhanced Akt phosphorylation in response to IGF-I and increased β-catenin signaling through two mechanisms: 1) stimulation of its cytosolic accumulation and 2) increased phosphorylation of serine 552. We conclude that the HBD peptide of IGFBP-2 has anabolic activity by activating IGF-I/Akt and β-catenin signaling pathways. These data support a growing body of evidence that IGFBP-2 is not just a transport protein but rather that it functions coordinately with IGF-I to stimulate growth and skeletal acquisition.
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Affiliation(s)
- Masanobu Kawai
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, Maine 04074, USA
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Muhlbradt E, Asatiani E, Ortner E, Wang A, Gelmann EP. NKX3.1 activates expression of insulin-like growth factor binding protein-3 to mediate insulin-like growth factor-I signaling and cell proliferation. Cancer Res 2009; 69:2615-22. [PMID: 19258508 DOI: 10.1158/0008-5472.can-08-3022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
NKX3.1 is a homeobox gene that codes for a haploinsufficient prostate cancer tumor suppressor. NKX3.1 protein levels are down-regulated in the majority of primary prostate cancer tissues. NKX3.1 expression in PC-3 cells increased insulin-like growth factor binding protein-3 (IGFBP-3) mRNA expression 10-fold as determined by expression microarray analysis. In both stably and transiently transfected PC-3 cells and in LNCaP cells, NKX3.1 expression increased IGFBP-3 mRNA and protein expression. In prostates of Nkx3.1 gene-targeted mice Igfbp-3 mRNA levels correlated with Nkx3.1 copy number. NKX3.1 expression in PC-3 cells attenuated the ability of insulin-like growth factor-I (IGF-I) to induce phosphorylation of type I IGF receptor (IGF-IR), insulin receptor substrate 1, phosphatidylinositol 3-kinase, and AKT. The effect of NKX3.1 on IGF-I signaling was not seen when cells were exposed to long-R3-IGF-I, an IGF-I variant peptide that does not bind to IGFBP-3. Additionally, small interfering RNA-induced knockdown of IGFBP-3 expression partially reversed the attenuation of IGF-IR signaling by NKX3.1 and abrogated NKX3.1 suppression of PC-3 cell proliferation. Thus, there is a close relationship in vitro and in vivo between NKX3.1 and IGFBP-3. The growth-suppressive effects of NKX3.1 in prostate cells are mediated, in part, by activation of IGFBP-3 expression.
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Affiliation(s)
- Erin Muhlbradt
- Lombardi Comprehensive Cancer Center, Washington, District of Columbia, USA
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Miyako K, Cobb LJ, Francis M, Huang A, Peng B, Pintar JE, Ariga H, Cohen P. PAPA-1 Is a nuclear binding partner of IGFBP-2 and modulates its growth-promoting actions. Mol Endocrinol 2008; 23:169-75. [PMID: 19095771 DOI: 10.1210/me.2008-0168] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
IGF-binding proteins (IGFBPs) have multiple cellular effects, which occur by both IGF-dependent and -independent mechanisms. IGFBP-2 is involved in the regulation of both normal and carcinogenic cell growth. To further understand the actions of IGFBP-2, we carried out a yeast two-hybrid screen to search for intracellular partner proteins using a human prostate cDNA library. We isolated Pim-1-associated protein-1 (PAP-1)-associated protein-1 (PAPA-1) as an IGFBP-2-binding protein, whose expression and subcellular localization is regulated by both IGFBP-2 and androgens. Coimmunoprecipitation and glutathione S-transferase pull-down assay confirmed the interaction in vitro, and confocal microscopy showed the colocalization of IGFBP-2 and PAPA-1 in the nucleus. Suppression of PAPA-1 by small interfering RNA treatment enhanced the growth-promoting effect of IGFBP-2. Conversely, IGFBP-2-promoted bromodeoxyuridine incorporation into LNCaP cells was abrogated by the simultaneous overexpression of myc-hPAPA-1. Mouse embryonic fibroblasts from IGFBP-2 knockout mouse showed diminished growth activity compared with wild type, and expression of FLAG-mPAPA-1 decreased cell proliferation in IGFBP-2 knockout, but not control mouse embryonic fibroblasts. These studies suggest that the growth-promoting role of IGFBP-2 in prostate cancer is inhibited by its intracellular interaction with PAPA-1.
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Affiliation(s)
- Kenichi Miyako
- David Geffen School of Medicine at University of California, Los Angeles, California 90095-1752, USA
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Zhou J, Li W, Kamei H, Duan C. Duplication of the IGFBP-2 gene in teleost fish: protein structure and functionality conservation and gene expression divergence. PLoS One 2008; 3:e3926. [PMID: 19081843 PMCID: PMC2593780 DOI: 10.1371/journal.pone.0003926] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 11/17/2008] [Indexed: 12/01/2022] Open
Abstract
Background Insulin-like growth factor binding protein-2 (IGFBP-2) is a secreted protein that binds and regulates IGF actions in controlling growth, development, reproduction, and aging. Elevated expression of IGFBP-2 is often associated with progression of many types of cancers. Methodology/Principal Findings We report the identification and characterization of two IGFBP-2 genes in zebrafish and four other teleost fish. Comparative genomics and structural analyses suggest that they are co-orthologs of the human IGFBP-2 gene. Biochemical assays show that both zebrafish igfbp-2a and -2b encode secreted proteins that bind IGFs. These two genes exhibit distinct spatiotemporal expression patterns. During embryogenesis, IGFBP-2a mRNA is initially detected in the lens, then in the brain boundary vasculature, and subsequently becomes highly expressed in the liver. In the adult stage, liver has the highest levels of IGFBP-2a mRNA, followed by the brain. Low levels of IGFBP-2a mRNA were detected in muscle and in the gonad in male adults only. IGFBP-2b mRNA is detected initially in all tissues at low levels, but later becomes abundant in the liver. In adult males, IGFBP-2b mRNA is only detected in the liver. In adult females, it is also found in the gut, kidney, ovary, and muscle. To gain insights into how the IGFBP-2 genes may have evolved through partitioning of ancestral functions, functional and mechanistic studies were carried out. Expression of zebrafish IGFBP-2a and -2b caused significant decreases in the growth and developmental rates and their effects are comparable to that of human IGFBP-2. IGFBP-2 mutants with altered IGF binding-, RGD-, and heparin-binding sites were generated and their actions examined. While mutating the RGD and heparin binding sites had little effect, altering the IGF binding site abolished its biological activity. Conclusions/Significance These results suggest that IGFBP-2 is a conserved regulatory protein and it inhibits growth and development primarily by binding to and inhibiting IGF actions in vivo. The duplicated IGFBP-2 genes may provide additional flexibility in the regulation of IGF activities.
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Affiliation(s)
- Jianfeng Zhou
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Laboratory of Molecular Medicine, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Wenhong Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Aquaculture, Guangxi University, Nanning, China
| | - Hiroyasu Kamei
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Cunming Duan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Laboratory of Molecular Medicine, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
- * E-mail:
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Palmieri C, Loi P, Ptak G, Della Salda L. Review Paper: A Review of the Pathology of Abnormal Placentae of Somatic Cell Nuclear Transfer Clone Pregnancies in Cattle, Sheep, and Mice. Vet Pathol 2008; 45:865-80. [DOI: 10.1354/vp.45-6-865] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cloning of cattle, sheep, and mice by somatic cell nuclear transfer (SCNT) can result in apparently healthy offspring, but the probability of a successful and complete pregnancy is less than 5%. Failures of SCNT pregnancy are associated with placental abnormalities, such as placentomegaly, reduced vascularisation, hypoplasia of trophoblastic epithelium, and altered basement membrane. The pathogenesis of these changes is poorly understood, but current evidence implicates aberrant reprogramming of donor nuclei by the recipient oocyte cytoplast, resulting in epigenetic modifications of key regulatory genes essential for normal placental development. The purpose of this review is to provide an overview of the anatomic pathology of abnormal placentae of SCNT clones and to summarize current knowledge concerning underlying pathogenetic mechanisms.
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Affiliation(s)
- C. Palmieri
- Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - P. Loi
- Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - G. Ptak
- Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - L. Della Salda
- Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
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36
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Yakar S, Rosen CJ, Bouxsein ML, Sun H, Mejia W, Kawashima Y, Wu Y, Emerton K, Williams V, Jepsen K, Schaffler MB, Majeska RJ, Gavrilova O, Gutierrez M, Hwang D, Pennisi P, Frystyk J, Boisclair Y, Pintar J, Jasper H, Domene H, Cohen P, Clemmons D, LeRoith D. Serum complexes of insulin-like growth factor-1 modulate skeletal integrity and carbohydrate metabolism. FASEB J 2008; 23:709-19. [PMID: 18952711 DOI: 10.1096/fj.08-118976] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Serum insulin-like growth factor (IGF) -1 is secreted mainly by the liver and circulates bound to IGF-binding proteins (IGFBPs), either as binary complexes or ternary complexes with IGFBP-3 or IGFBP-5 and an acid-labile subunit (ALS). The purpose of this study was to genetically dissect the role of IGF-1 circulatory complexes in somatic growth, skeletal integrity, and metabolism. Phenotypic comparisons of controls and four mouse lines with genetic IGF-1 deficits-liver-specific IGF-1 deficiency (LID), ALS knockout (ALSKO), IGFBP-3 (BP3) knockout, and a triply deficient LID/ALSKO/BP3 line-produced several novel findings. 1) All deficient strains had decreased serum IGF-1 levels, but this neither predicted growth potential or skeletal integrity nor defined growth hormone secretion or metabolic abnormalities. 2) IGF-1 deficiency affected development of both cortical and trabecular bone differently, effects apparently dependent on the presence of different circulating IGF-1 complexes. 3) IGFBP-3 deficiency resulted in increased linear growth. In summary, each IGF-1 complex constituent appears to play a distinct role in determining skeletal phenotype, with different effects on cortical and trabecular bone compartments.
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Affiliation(s)
- Shoshana Yakar
- Endocrinology/Diabetes and Bone Disease, The Mt. Sinai School of Medicine, One Gustave L Levy Place, Box 1055, New York, NY 10029-6574, USA.
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37
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DeMambro VE, Clemmons DR, Horton LG, Bouxsein ML, Wood TL, Beamer WG, Canalis E, Rosen CJ. Gender-specific changes in bone turnover and skeletal architecture in igfbp-2-null mice. Endocrinology 2008; 149:2051-61. [PMID: 18276763 PMCID: PMC2329262 DOI: 10.1210/en.2007-1068] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
IGF-binding protein-2 (IGFBP-2) is a 36-kDa protein that binds to the IGFs with high affinity. To determine its role in bone turnover, we compared Igfbp2(-/-) mice with Igfbp2(+/+) colony controls. Igfbp2(-/-) males had shorter femurs and were heavier than controls but were not insulin resistant. Serum IGF-I levels in Igfbp2(-/-) mice were 10% higher than Igfbp2(+/+) controls at 8 wk of age; in males, this was accompanied by a 3-fold increase in hepatic Igfbp3 and Igfbp5 mRNA transcripts compared with Igfbp2(+/+) controls. The skeletal phenotype of the Igfbp2(-/-) mice was gender and compartment specific; Igfbp2(-/-) females had increased cortical thickness with a greater periosteal circumference compared with controls, whereas male Igfbp2(-/-) males had reduced cortical bone area and a 20% reduction in the trabecular bone volume fraction due to thinner trabeculae than Igfbp2(+/+) controls. Serum osteocalcin levels were reduced by nearly 40% in Igfbp2(-/-) males, and in vitro, both CFU-ALP(+) preosteoblasts, and tartrate-resistant acid phosphatase-positive osteoclasts were significantly less abundant than in Igfbp2(+/+) male mice. Histomorphometry confirmed fewer osteoblasts and osteoclasts per bone perimeter and reduced bone formation in the Igfbp2(-/-) males. Lysates from both osteoblasts and osteoclasts in the Igfbp2(-/-) males had phosphatase and tensin homolog (PTEN) levels that were significantly higher than Igfbp2(+/+) controls and were suppressed by addition of exogenous IGFBP-2. In summary, there are gender- and compartment-specific changes in Igfbp2(-/-) mice. IGFBP-2 may regulate bone turnover in both an IGF-I-dependent and -independent manner.
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Affiliation(s)
- V E DeMambro
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA.
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38
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Huynh H, Iizuka S, Kaba M, Kirak O, Zheng J, Lodish HF, Zhang CC. Insulin-like growth factor-binding protein 2 secreted by a tumorigenic cell line supports ex vivo expansion of mouse hematopoietic stem cells. Stem Cells 2008; 26:1628-35. [PMID: 18369099 DOI: 10.1634/stemcells.2008-0064] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Successful hematopoietic stem cell (HSC) transplantation is often limited by the numbers of HSCs, and robust methods to expand HSCs ex vivo are needed. We previously showed that angiopoietin-like proteins (Angptls), a group of growth factors isolated from a fetal liver HSC-supportive cell population, improved ex vivo expansion of HSCs. Here, we demonstrate that insulin-like growth factor-binding protein 2 (IGFBP2), secreted by a tumorigenic cell line, also enhanced ex vivo expansion of mouse HSCs. On the basis of these findings, we established a completely defined, serum-free culture system for mouse HSCs, containing SCF, thrombopoietin, fibroblast growth factor 1, Angptl3, and IGFBP2. As measured by competitive repopulation analyses, there was a 48-fold increase in numbers of long-term repopulating mouse HSCs after 21 days of culture. This is the first demonstration that IGFBP2 stimulates expansion or proliferation of murine stem cells. Our finding also suggests that certain cancer cells synthesize proteins that can stimulate HSC expansion. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Hoangdinh Huynh
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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39
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McDonald TJ, Nijland MJ, Nathanielsz PW. The insulin-like growth factor system and the fetal brain: effects of poor maternal nutrition. Rev Endocr Metab Disord 2007; 8:71-84. [PMID: 17653868 DOI: 10.1007/s11154-007-9044-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The insulin-like growth factor (IGF) signaling system plays indispensable roles in pre- and post-natal brain growth and development. A large body of studies using both in vivo null mutant and transgenic mice and in vitro neuronal culture techniques indicate that IGF-I acts directly on the brain while IGF-II effects are mediated to a large extent by IGF-II control of placental growth. It appears that all of the mechanisms, except migration, that are involved in normal brain development, e.g., proliferation, apoptosis, maturation and differentiation, are influenced by IGF-I. While IGF system members are produced in the brain, recent reports in post-natal animals indicate that normal brain health and function are dependent upon transfer of circulating IGF-I from the liver and its transfer across the blood brain barrier. Data showing that this phenomenon applies to pre-natal brain growth and development would make an important contribution to fetal physiology. A number of kinase pathways are able to participate in IGF signaling in brain with respect to nutrient restriction; among the most important are the PI3K/AKT, Ras-Raf-MEK-ERK and mTOR-nutrient sensing pathways. Both maternal and fetal IGF-I peripheral plasma concentrations are greatly reduced in nutrient restriction while IGF-II does not appear to be affected. Nutrient restriction also affects IGF binding protein concentrations while effects on the IGF-I receptor appear to vary with the paradigm. Studies on the effects of nutrient restriction on the fetal primate brain in relation to activity of the IGF system are needed to determine the applicability of rodent studies to humans.
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Affiliation(s)
- Thomas J McDonald
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX 78253, USA
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40
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Ning Y, Hoang B, Schuller AGP, Cominski TP, Hsu MS, Wood TL, Pintar JE. Delayed mammary gland involution in mice with mutation of the insulin-like growth factor binding protein 5 gene. Endocrinology 2007; 148:2138-47. [PMID: 17255210 DOI: 10.1210/en.2006-0041] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
IGFs (IGF-I and IGF-II) are essential for development, and their bioactivities are tightly regulated by six related IGF-binding proteins (IGFBPs). IGFBP-5 is the most highly conserved binding protein and is expressed in several key developmental lineages as well as in multiple adult tissues including the mammary gland. To explore IGFBP-5 actions in vivo, we produced IGFBP-5 knockout (KO) mice. Whole-body growth, selected organ weights, and body composition were essentially normal in IGFBP-5 KO mice, presumably because of substantial compensation by remaining IGFBP family members. The IGFBP-5 KO mice also exhibited normal mammary gland development and were capable of nursing their pups. We then directly evaluated the proposed role of IGFBP-5 in apoptosis and remodeling of mammary gland during involution. We found that the process of involution after forced weaning was delayed in IGFBP-5 KO mice, with both the appearance of apoptotic cells and the reappearance of adipocytes retarded in mutant mice, compared with controls. We also determined the effects of IGFBP-5 deletion on mammary gland development in pubertal females after ovariectomy and stimulation with estradiol/progesterone. In this paradigm, IGFBP-5 KO mammary glands exhibited enhanced alveolar bud formation consistent with enhanced IGF-I action. These results demonstrate that IGFBP-5, although not essential for normal growth, is required for normal mammary gland involution and can regulate mammary gland morphogenesis in response to hormone stimulation.
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Affiliation(s)
- Yun Ning
- Department of Neuroscience, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA
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41
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Wheatcroft SB, Kearney MT, Shah AM, Ezzat VA, Miell JR, Modo M, Williams SCR, Cawthorn WP, Medina-Gomez G, Vidal-Puig A, Sethi JK, Crossey PA. IGF-binding protein-2 protects against the development of obesity and insulin resistance. Diabetes 2007; 56:285-94. [PMID: 17259371 PMCID: PMC4295171 DOI: 10.2337/db06-0436] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Proliferation of adipocyte precursors and their differentiation into mature adipocytes contributes to the development of obesity in mammals. IGF-I is a potent mitogen and important stimulus for adipocyte differentiation. The biological actions of IGFs are closely regulated by a family of IGF-binding proteins (IGFBPs), which exert predominantly inhibitory effects. IGFBP-2 is the principal binding protein secreted by differentiating white preadipocytes, suggesting a potential role in the development of obesity. We have generated transgenic mice overexpressing human IGFBP-2 under the control of its native promoter, and we show that overexpression of IGFBP-2 is associated with reduced susceptibility to obesity and improved insulin sensitivity. Whereas wild-type littermates developed glucose intolerance and increased blood pressure with aging, mice overexpressing IGFBP-2 were protected. Furthermore, when fed a high-fat/high-energy diet, IGFBP-2-overexpressing mice were resistant to the development of obesity and insulin resistance. This lean phenotype was associated with decreased leptin levels, increased glucose sensitivity, and lower blood pressure compared with wild-type animals consuming similar amounts of high-fat diet. Our in vitro data suggest a direct effect of IGFBP-2 preventing adipogenesis as indicated by the ability of recombinant IGFBP-2 to impair 3T3-L1 differentiation. These findings suggest an important, novel role for IGFBP-2 in obesity prevention.
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Affiliation(s)
- Stephen B Wheatcroft
- Academic Unit of Cardiovascular Medicine, The LIGHT Laboratories, Clarendon Way, University of Leeds, Leeds LS2 9JT, U.K
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42
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Grimberg A, Coleman CM, Shi Z, Burns TF, MacLachlan TK, Wang W, El-Deiry WS. Insulin-like growth factor factor binding protein-2 is a novel mediator of p53 inhibition of insulin-like growth factor signaling. Cancer Biol Ther 2006; 5:1408-14. [PMID: 17102589 PMCID: PMC1906874 DOI: 10.4161/cbt.5.10.3455] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The p53 tumor suppressor induces cellular growth arrest and apoptosis in response to DNA damage by transcriptionally activating or repressing target genes and also through protein-protein interactions and direct mitochondrial activities. In 1995, insulin-like growth factor binding protein (IGFBP)-3 was identified as one of the genes transcriptionally activated by p53. IGFBP-3 is one of six closely related IGFBP's, with additional IGFBP-related proteins belonging to the IGFBP superfamily. Here we show that IGFBP-2 is also a p53 target. Like IGFBP-3, IGFBP-2 secretion is reduced when p53+/+ lung cancer cells are transfected with human papillomavirus E6, which targets p53 for degradation. IGFBP-2 mRNA is induced by irradiation in vivo in a p53-dependent manner. p53 protein binds IGFBP-2 intronic sequences in an electrophoretic mobility shift assay, and activates transcription in a luciferase assay. Loss of IGFBP-2 inhibits the ability of p53 to inhibit the activation of extracellular signal-regulated kinase (ERK)1 by IGF-I. Thus, p53 effects on the IGF axis are more complex than previously appreciated, and overall transform the axis from IGF-mediated mitogenesis to growth inhibition and apoptosis. This has significant implications for how growth hormone and IGF-I can induce growth without also inducing cancer.
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Affiliation(s)
- Adda Grimberg
- Department of Pediatrics, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia, Pennsylvania 19104-4318, USA.
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43
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Ning Y, Schuller AGP, Bradshaw S, Rotwein P, Ludwig T, Frystyk J, Pintar JE. Diminished growth and enhanced glucose metabolism in triple knockout mice containing mutations of insulin-like growth factor binding protein-3, -4, and -5. Mol Endocrinol 2006; 20:2173-86. [PMID: 16675541 DOI: 10.1210/me.2005-0196] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
IGF-I and IGF-II are essential regulators of mammalian growth, development and metabolism, whose actions are modified by six high-affinity IGF binding proteins (IGFBPs). New lines of knockout (KO) mice lacking either IGFBP-3, -4, or -5 had no apparent deficiencies in growth or metabolism beyond a modest growth impairment (approximately 85-90% of wild type) when IGFBP-4 was eliminated. To continue to address the roles of these proteins in whole animal physiology, we generated combinational IGFBP KO mice. Mice homozygous for targeted defects in IGFBP-3, -4, and -5 remain viable and at birth were the same size as IGFBP-4 KO mice. Unlike IGFBP-4 KO mice, however, the triple KO mice became significantly smaller by adulthood (78% wild type) and had significant reductions in fat pad accumulation (P < 0.05), circulating levels of total IGF-I (45% of wild type; P < 0.05) and IGF-I bioactivity (37% of wild type; P < 0.05). Metabolically, triple KO mice showed normal insulin tolerance, but a 37% expansion (P < 0.05) of beta-cell number and significantly increased insulin secretion after glucose challenge, which leads to enhanced glucose disposal. Finally, triple KO mice demonstrated a tissue-specific decline in activation of the Erk signaling pathway as well as weight of the quadriceps muscle. Taken together, these data provide direct evidence for combinatorial effects of IGFBP-3, -4, and -5 in both metabolism and at least some soft tissues and strongly suggest overlapping roles for IGFBP-3 and -5 in maintaining IGF-I-mediated postnatal growth in mice.
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Affiliation(s)
- Yun Ning
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA
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44
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Terrien X, Bonvin E, Corroyer S, Tabary O, Clement A, Henrion Caude A. Intracellular colocalization and interaction of IGF-binding protein-2 with the cyclin-dependent kinase inhibitor p21CIP1/WAF1 during growth inhibition. Biochem J 2005; 392:457-65. [PMID: 16131350 PMCID: PMC1316284 DOI: 10.1042/bj20050517] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 08/23/2005] [Accepted: 08/30/2005] [Indexed: 01/07/2023]
Abstract
It is presently unknown whether any member of the IGFBP (insulin-like growth factor binding protein) family directly participates in the control of cell proliferation. We have previously documented that induction of IGFBP-2 was associated with inhibition of DNA synthesis in lung alveolar epithelial cells. In the present study, we investigated the relationship between IGFBP-2 and the cell cycle inhibitor p21CIP1/WAF1 further. We used serum deprivation to inhibit the proliferation of MLE (mouse lung epithelial)-12 cells, and characterized the spatial localization of IGFBP-2. We found that growth inhibition, which was supported by the strong induction of p21CIP1/WAF1, was correlated with increased secretion of IGFBP-2 and, unexpectedly, with its increased localization in the nucleus and particularly in the cytoplasm. By coimmunoprecipitation, we discovered that IGFBP-2 is capable of binding to p21CIP1/WAF1. Interaction between these two proteins was further supported by colocalization of the proteins within growth-arrested cells, as visualized by confocal microscopy. Furthermore, this interaction increased with the duration of the stress, but was suppressed when proliferation was restimulated by the addition of serum. The recombinant expression of GFP (green fluorescent protein)-tagged IGFBP-2 in transfected MLE-12 cells demonstrated its ability to bind specifically to p21CIP1/WAF1. Taken together, these results provide a link between IGFBP-2 and p21CIP1/WAF1 in the regulation of alveolar lung cell proliferation.
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Affiliation(s)
- Xavier Terrien
- INSERM U719, Université Pierre et Marie Curie, Hôpital St-Antoine, 75571 Paris Cedex 12, France
| | - Elise Bonvin
- INSERM U719, Université Pierre et Marie Curie, Hôpital St-Antoine, 75571 Paris Cedex 12, France
| | - Sophie Corroyer
- INSERM U719, Université Pierre et Marie Curie, Hôpital St-Antoine, 75571 Paris Cedex 12, France
| | - Olivier Tabary
- INSERM U719, Université Pierre et Marie Curie, Hôpital St-Antoine, 75571 Paris Cedex 12, France
| | - Annick Clement
- INSERM U719, Université Pierre et Marie Curie, Hôpital St-Antoine, 75571 Paris Cedex 12, France
| | - Alexandra Henrion Caude
- INSERM U719, Université Pierre et Marie Curie, Hôpital St-Antoine, 75571 Paris Cedex 12, France
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45
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Russo VC, Gluckman PD, Feldman EL, Werther GA. The insulin-like growth factor system and its pleiotropic functions in brain. Endocr Rev 2005; 26:916-43. [PMID: 16131630 DOI: 10.1210/er.2004-0024] [Citation(s) in RCA: 355] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In recent years, much interest has been devoted to defining the role of the IGF system in the nervous system. The ubiquitous IGFs, their cell membrane receptors, and their carrier binding proteins, the IGFBPs, are expressed early in the development of the nervous system and are therefore considered to play a key role in these processes. In vitro studies have demonstrated that the IGF system promotes differentiation and proliferation and sustains survival, preventing apoptosis of neuronal and brain derived cells. Furthermore, studies of transgenic mice overexpressing components of the IGF system or mice with disruptions of the same genes have clearly shown that the IGF system plays a key role in vivo.
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Affiliation(s)
- V C Russo
- Centre for Hormone Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia.
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46
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Peters LL, Zhang W, Lambert AJ, Brugnara C, Churchill GA, Platt OS. Quantitative trait loci for baseline white blood cell count, platelet count, and mean platelet volume. Mamm Genome 2005; 16:749-63. [PMID: 16261417 DOI: 10.1007/s00335-005-0063-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Accepted: 06/29/2005] [Indexed: 11/29/2022]
Abstract
A substantial genetic contribution to baseline peripheral blood counts has been established. We performed quantitative trait locus/loci (QTL) analyses to identify chromosome (Chr) regions harboring genes influencing the baseline white blood cell (WBC) count, platelet (Plt) count, and mean platelet volume (MPV) in F(2) intercrosses between NZW/LacJ, SM/J, and C57BLKS/J inbred mice. We identified six significant WBC QTL: Wbcq1 (peak LOD score at 38 cM, Chr 1), Wbcq2 (42 cM, Chr 3), Wbcq3 (0 cM, Chr 15), Wbcq4 (58 cM, Chr 1), Wbcq5 (82 cM, Chr 1), and Wbcq6 (8 cM, Chr 14). Three significant Plt QTL were identified: Pltq1 (24 cM, Chr 2), Pltq2 (36 cM, Chr 7), and Pltq3 (10 cM, Chr 12). Two significant MPV QTL were identified, Mpvq1 (62 cM, Chr 15) and Mpvq2 (44 cM, Chr 8). In total, the WBC QTL accounted for up to 31% of the total variance in baseline WBC count, while the Plt and MPV QTL accounted for up to 30% and 49% of the total variance, respectively. These analyses underscore the genetic complexity underlying these traits in normal populations and provide the basis for future studies to identify novel genes involved in the regulation of mammalian hematopoiesis.
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Affiliation(s)
- Luanne L Peters
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA.
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47
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Pell JM, Salih DAM, Cobb LJ, Tripathi G, Drozd A. The role of insulin-like growth factor binding proteins in development. Rev Endocr Metab Disord 2005; 6:189-98. [PMID: 16151623 DOI: 10.1007/s11154-005-3050-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- J M Pell
- Babraham Institute, Babraham Research Campus, Cambridge, CB2 4AT, UK
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48
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Gordon PV, Paxton JB, Kuemmerle JF, Fox NS. A 14-kDa cathepsin L-derived carboxyl IGFBP-2 fragment is sequestered by cultured rat ileal crypt cells. Am J Physiol Gastrointest Liver Physiol 2005; 289:G79-87. [PMID: 15705658 DOI: 10.1152/ajpgi.00384.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
IGF-II gut drives mucosal growth during gestation. IGF binding protein-2 (IGFBP-2) has a high affinity for IGF-II and tightly regulates IGF-II availability during fetal and early neonatal growth. We have previously demonstrated that glucocorticoids alter IGF homeostasis in the neonatal ileum, but the mechanism(s) by which this occurs is poorly understood. We hypothesized that dexamethasone alters proteolytic regulation of IGFBP-2 in ileal crypt cells. To test this, ileal crypt [ileal epithelial (IEC)-18] cells were cultured in serum-free media and used to study IGFBP-2 catabolism by immunochemistry, gene array analysis, and pharmacological perturbation with dexamethasone. In addition, isolated human IGFBP-2, IGF-II, and cathepsins B, D, and L were utilized for in vitro protease assays. We found IGFBP-2 to be highly abundant in IEC-18 culture, and sequestration of carboxyl IGFBP-2 antigen was seen within vesicular bodies of some cells. Dexamethasone significantly decreased the number of these cells and decreased IGFBP-2 in the media. On gene array analysis, cathepsin L's message abundance was significantly increased by dexamethasone, and, by in vitro assay, cathepsin L created a 14-kDa carboxyl fragment that corresponded to the sole antigen detected in IEC-18 cell lysates as well as a 16.5-kDa fragment found in the media. The sequestered fragment size was formed preferentially when IGF-II was present, whereas the larger fragment size was formed preferentially when IGF-II was absent. Cathepsins B and D did not produce these fragments in vitro and were not detected in IEC-18 media. We conclude that dexamethasone alters IGFBP-2 catabolism through its effects on cathepsin L.
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Affiliation(s)
- Phillip V Gordon
- Division of Neonatology, Department of Pediatrics, University of Virginia Health Sciences, Charlottesville, VA 22908, USA.
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49
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Foulstone E, Prince S, Zaccheo O, Burns JL, Harper J, Jacobs C, Church D, Hassan AB. Insulin-like growth factor ligands, receptors, and binding proteins in cancer. J Pathol 2005; 205:145-53. [PMID: 15641016 DOI: 10.1002/path.1712] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
This review aims to summarize experimental evidence supporting the role of the insulin-like growth factor (IGF) signalling system in the progression, maintenance, and treatment of cancer. These data implicate the IGF system as an important modifier of cancer cell proliferation, survival, growth, and treatment sensitivity. The role of the IGF system in cancer should be examined in the context of the extra-cellular and intra-cellular signalling networks, in particular: phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt/PKB), mammalian target of rapamycin (mTOR), and forkhead transcription factors (FOXO). This review highlights evidence derived from molecular structure and functional genetics with respect to how the extra-cellular components of the IGF system function normally, and their subsequent modifications in cancer. The therapeutic relevance of the research evidence described is also addressed, as the challenge is to apply this knowledge to human health.
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Affiliation(s)
- E Foulstone
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
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50
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Wolf E, Schneider MR, Zhou R, Fisch TM, Herbach N, Dahlhoff M, Wanke R, Hoeflich A. Functional consequences of IGFBP excess-lessons from transgenic mice. Pediatr Nephrol 2005; 20:269-78. [PMID: 15602658 DOI: 10.1007/s00467-004-1657-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 07/26/2004] [Accepted: 07/26/2004] [Indexed: 11/29/2022]
Abstract
The functions of insulin-like growth factor-binding proteins (IGFBPs) have been studied extensively in vitro, revealing IGF-dependent and also IGF-independent effects on cell growth, differentiation, and survival. In contrast, the biological relevance of IGFBPs in vivo is only partially understood. In the past decade, mouse models lacking or overexpressing specific IGFBPs have been generated by transgenic technology. Phenotypic analysis revealed features that are common for most IGFBPs (growth inhibition), but also effects that appear to be specific for some but not all IGFBPs, such as disturbed glucose homeostasis (IGFBP-1 and -3) or impaired fertility (IGFBP-1, -5, and -6). Future systematic comparison of IGFBP functions in transgenic mice will be facilitated by targeted insertion of IGFBP expression vectors and by standardized phenotype assessment. Furthermore, analysis of IGFBP expression in growth-selected mouse lines or pedigrees segregating for growth phenotypes will be important to understand the roles of IGFBPs in multigenic growth regulation.
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Affiliation(s)
- Eckhard Wolf
- Institute of Molecular Animal Breeding and Biotechnology/Gene Center, Munich, Germany.
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